Endometrial Stromal Sarcoma With Hyalinizing Giant Rosettes, Mimicking Low-Grade Fibromyxoid Sarcoma.

We highlight a rare variant pattern of low-grade endometrial stromal sarcoma showing extensive collagenous rosette formation, closely mimicking low-grade fibromyxoid sarcoma. Additionally, this neoplasm showed diffuse and strong expression of muscle markers, favoring an initial diagnosis of leiomyosarcoma. Reverse transcription-polymerase chain reaction showed the presence of JAZF1-SUZ12 fusion transcripts, and this highlights the broad morphologic and immunophenotypic spectrum of endometrial stromal sarcoma.